Self-loading pistols having: (1) a grip; (2) a barrel which is supported firmly on this grip; (3) a breech which is arranged at least partially behind the barrel and moves in the longitudinal direction of the barrel between a front closed position and a rear open position; and (4) a multiple turn, helical return spring which forces the breech into the closed position and, when the breech is in the open position is compressed such that all the turns of the spring are seated on one another are known in the art. For example, such a pistol has been disclosed in German Patent DE 41 09 777 C and is manufactured by HECKLER & KOCH.
Relatively powerful pistol cartridges, (e.g., the 9 mm Parabellum cartridge), are, as a rule, fired from locked self-loading pistols. In these pistols, a locking device generally firmly connects the barrel and the breech to one another such that, when driven by the recoil of a fired cartridge, the barrel and the breech initially travel through a common recoil distance. The breech only separates from the barrel after this common recoil distance has been traversed. After separation, the breech continues through a further recoil movement without the barrel. During this process, the empty cartridge case is ejected, a trigger device is cocked, and the next cartridge is fed.
However, with most of these powerful cartridges, it is also possible to use an unlocked blowback breech if the force of the return spring and/or the mass of the breech are chosen to be sufficiently high. Such blowback breeches are admittedly in widespread use in machine pistols. However, in such weapons, not only the mass but also the kinetic energy of the closing breech are used to support the barrel during firing.
Pistols with a blowback breech which fire cartridges of the type mentioned initially are admittedly known. However, not only is the weight of such pistols heavy overall, but they also have an excessively powerful return spring. Because of this return spring, slide retraction is very tedious and can often be carried out only after sufficient practice. For this reason, only locked pistols are used nowadays for powerful pistol cartridges of the type mentioned initially.
Pistol cartridges of the foregoing type are often available with particularly lightly filled loads. These lightly filled cartridges are used, for example, for sports shooting. This allows the hit result to be optimized, the amount of noise produced to be reduced, the bullet trap to be protected or the cartridge cases to be protected in a very simple manner during reloading, the powder consumption to be reduced, and thus the costs of shooting to be reduced.
Such lightly filled cartridges can also be fired in locked self-loading pistols whose locking devices are adapted to conventional normal ammunition. However, the recoil developed by firing such cartridges is insufficient to achieve reliable slide retraction in such weapons. Normally, the weapons simply remain closed and slide retraction must be carried out by hand after every shot. The pistol with a blowback breech described above also cannot carry out automatic slide retraction when such ammunition is fired because, for example, its breech is too heavy. As a result, firing practices which require a number of shots to be fired quickly cannot be carried out with such weapons and such weak ammunition.
A small caliber retrofitting kit having a small caliber barrel and an unlocked blowback breech adapted to it is known for use in many locked pistols (mostly military pistols). This small caliber barrel and the blowback action can be mounted on the grip of the locked pistol. After installation, one then has a small caliber pistol, which is very similar in handling, trigger weight, etc. to the original locked pistol. Such a pistol is shown, for example, in U.S. Pat. No. 1,563,675. In this known small caliber retrofitting kit, the guide rod for the small caliber closure spring is quite long. Therefore, a buffer sleeve sits on the rear end of this rod. The small caliber closure spring is supported on the front end of this buffer sleeve. Naturally, when retrofitted to a small caliber, this pistol is not suitable for firing a cartridge that can be loaded into the original locked pistol. Even if the unlocked retrofitting system were designed for the same cartridge as the unlocked pistol, one would have to contend with the difficulties that were already described in conjunction with heavy pistols with blowback action.
Cartridges of the abovementioned type (for example 9 mm Parabellum) also exist in a shot version. In this case, they are only lightly filled in order to achieve satisfactory composition of the shot stringing. Such cartridges are often used for defence against snakes by hunters, hikers, lumberjacks etc. in areas where there is a snake hazard. Such a cartridge is normally loaded into the firing chamber of a self-loading pistol while the magazine is loaded with conventional (powerfully filled) bullets. The shot cartridge is then ready for use if a snake is encountered. If, however, instead of a snake, one encounters a relatively large predatory animal, (e.g., a feral dog), then once the shot cartridge has been fired, the slide must be retracted by hand to ready the weapon for defence against the predator. After this first manual retraction, the self-loading pistol can be used in the normal manner.
Only revolvers offer the capability to load shot cartridges and bullets in any desired sequence and to fire them successively without any additional reloading process carried out by hand.
In view of the foregoing, it would be beneficial to provide: (1) a self-loading pistol which is set up to fire the lightly filled cartridges mentioned above; (2) a conversion kit, by means of which a conventional locked self-loading pistol which is set up to fire conventional ammunition, can also be converted to fire the lightly filled ammunition; and (3) a weapon system with a self-loading pistol which can optionally be set up to fire normal or lightly filled anmunition.
Because of the issues mentioned above, in practice, only an unlocked self-loading pistol is suitable for firing the lightly filled cartridges since releasing the lock consumes too much recoil energy so that the subsequent slide retraction process is no longer carried out reliably in a locked self-loading pistol.
To address this issue, it would in principle be possible just to transfer a blowback breech and a return spring force, as are used for light, normally unlocked pocket pistols, to pistols which are normally set up for the larger cartridges mentioned above. Such a measure would admittedly provide a functional pistol. However, if cartridges with a normal charge were accidentally fired from such a pistol, then the breech and the grip would rapidly be damaged at the point where these parts strike one another at the end of the recoil. Such a pistol would quickly become unusable even if it could, perhaps, withstand the firing of this much too powerful ammunition without (parts) breaking.